1. Field of the Invention
The present invention relates to improvements of a process and apparatus for assembling a vehicle body frame for a motorcycle by welding a front frame subassembly having a head pipe at a front end thereof and a rear frame subassembly to each other.
2. Description of the Related Art
A process for assembling a vehicle body frame for a motorcycle is conventionally known from Japanese Patent Publication No.4-749, for example. In this process, a center member such as a head pipe and a cross member is retained by a center jig, and left and right side frame members forming a vehicle body frame in cooperation with the center member are retained by a pair of left and right side jigs, respectively. In a state in which both of the side jigs have been righted, the side members are welded to opposite sides of the center member to assemble the vehicle body frame.
In the above conventionally known process, however, an exclusive center jig and exclusive side jigs corresponding to the type of the vehicle body frame are required. To assemble a plurality of types of vehicle body frames for motorcycles, center jigs and side jigs corresponding to the types must be prepared, resulting in an increased equipment cost.
The present invention has been accomplished in view of the above circumstances, and it is an object of the present invention to provide a process and apparatus for assembling a vehicle body frame for a motorcycle, wherein the general-purpose properties are provided to accommodate the assembling of any of a plurality of types of vehicle body frames for motorcycles, thereby providing a reduction in equipment cost.
To achieve the above object, according to a first aspect and feature of the present invention, there is provided a process for assembling a vehicle body frame for a motorcycle by welding a front frame subassembly having a head pipe at a front end thereof and a rear frame subassembly to each other to assemble the vehicle body frame for the motorcycle, comprising a first step of positioning left and right rear portions of the front frame subassembly by a pair of front positioning means movable at least in a direction of a Y-axis established in a widthwise direction of the vehicle body frame, a second step of clamping the head pipe at the front end of the front frame subassembly by a front clamp means which is capable of moving in directions of Z- and X-axes established in vertical and longitudinal directions of the vehicle body frame, and is capable of tilting about an axis extending along the Y-axis, a third step of positioning left and right rear portions of the rear frame subassembly by a pair of rear positioning means movable in the directions of the X-, Y- and Z-axes, a fourth step of clamping left and right front portions of the rear frame subassembly by a pair of rear clamp means movable in the directions of the X-, Y- and Z-axes, and a fifth step of welding the rear frame subassembly positioned relative to the front frame subassembly and the front frame subassembly to each other.
With such process, the pair of front positioning means for positioning the left and right rear portions of the front frame subassembly are movable at least in the widthwise direction of the vehicle body frame for the motorcycle, and the front clamp means for clamping the head pipe at the front end of the front frame subassembly is movable in the longitudinal and vertical directions of the vehicle body frame for the motorcycle and tiltable in the longitudinal direction of the vehicle body frame. Therefore, in a state in which the left and right rear portions of the front frame subassembly have been positioned by the front positioning means, changes in position and attitude of the head pipe caused by the change in type of the front frame subassembly can be covered by the movement of the front clamp means in the longitudinal and vertical directions and the tilting of the front clamp means about the Y-axis, whereby the front frame subassembly can be positioned and supported with a good accuracy. In addition, the pair of rear positioning means for positioning the left and right rear portions of the rear frame subassembly are movable in the longitudinal, widthwise and vertical directions of the vehicle body frame for the motorcycle, and the pair of rear clamp means for clamping the left and right front portions of the rear frame subassembly are movable in the longitudinal, widthwise and vertical directions of the vehicle body frame for the motorcycle. Therefore, even if the type of the rear frame subassembly is changed, the rear frame subassembly can be positioned and supported with a good accuracy relative to the front frame subassembly, thereby providing general-purpose properties to accommodate the assembling of any of a plurality of types of vehicle body frames for motorcycles, leading to a reduction in equipment cost. Moreover, the vehicle body frame having a stable welding accuracy can be assembled by welding the front and rear frame subassemblies positioned with a good accuracy relative to each other. Additionally, the rear frame subassembly is restrained while being positioned accurately relative to the front frame subassembly by the pair of rear positioning means and the pair of rear clamp means. Therefore, even if a welding strain has been produced in the rear frame subassembly, such strain can be corrected to assemble the vehicle body frame for the motorcycle with a good accuracy.
According to a second aspect and feature of the present invention, there is provided an apparatus for assembling a vehicle body frame for a motorcycle by welding a front frame subassembly having a head pipe at a front end thereof and a rear frame subassembly to each other, comprising a pair of front positioning means capable of positioning left and right rear portions of the front frame subassembly, a front clamp means capable of clamping the head pipe at the front end of the front frame subassembly, a pair of rear positioning means capable of positioning left and right rear portions of the rear frame subassembly, a pair of rear clamp means capable of clamping left and right front portions of the rear frame subassembly, a pair of front positioning drive means for moving the front positioning means at least in a direction of a Y-axis established in a widthwise direction of the vehicle body frame, respectively, a front clamp drive means which is capable of moving the front clamp means in directions of Z- and X-axes established in vertical and longitudinal directions of the vehicle body frame, and is capable of tilting the front clamp means about an axis extending along the Y-axis, a pair of rear positioning drive means capable of moving the rear positioning means in the directions of X-, Y- and Z-axes, respectively, a pair of rear clamp drive means capable of moving the rear clamp means in the directions of X-, Y- and Z-axes, respectively, and a control unit for controlling the operations of the drive means, so that the front positioning means, the front clamp means, the rear positioning means and the rear clamp means are brought into positions previously determined depending on the type of the vehicle body frame for the motorcycle, which is to be assembled.
With the arrangement of the second feature, the pair of front positioning means, the front clamp means, the pair of rear positioning means and the pair of rear clamp means are moved automatically to the positions corresponding to the vehicle body frame in accordance with the change in type of the vehicle body frame for the motorcycle, which is to be assembled. Therefore, the process of the first feature can be carried out appropriately with an enhanced efficiency of assembling of the vehicle body frame for the motorcycle.
According to a third aspect and feature of the present invention, in addition to the second feature, the front clamp means includes a plurality of supporting pins capable of being fitted into lower ends of a plurality of types of head pipes, a pin-supporting plate for fixedly supporting one of the supporting pins, while disposing the pin at a location below the head pipe, a pushing member capable of being brought into engagement with an upper end of the head pipe fitted at a lower end thereof over one of the supporting pins, irrespective of the type of the head pipe, thereby clamping the head pipe between the pushing member and the one of the supporting pins, and a cylinder for providing pushing force for pushing the head pipe from above to the pushing member.
With the arrangement of the third feature, the head pipe can be clamped between the supporting pin selected depending on the head pipe to be retained and the pushing member corresponding to any of the plurality of types of head pipes, thereby providing general-purpose properties to accommodate the assembling of any of the plurality of types of vehicle body frames for motorcycles, leading to a reduction in equipment cost.
According to a fourth aspect and feature of the present invention, in addition to the third feature, the apparatus further includes an arm, at one end of which the pushing member is mounted, the cylinder being disposed at a fixed position to have an axis parallel to an axis of the head pipe and connected to the other end of the arm through a connecting pin, a cam plate fixedly disposed with a position thereof fixed relative to the cylinder, and having a cam bore comprising a first bore portion extending in parallel to the axis of the head pipe, and a second bore portion connected to an upper end of the first bore portion and inclined in such a direction that the second bore portion is more spaced apart from the head pipe at an upper location, and a roller supported at an intermediate portion of the arm and capable of being rolled within the cam bore.
With the arrangement of the fourth feature, as the roller is rolled within the cam bore in response to the expansion and contraction of the cylinder, the arm is turned about the connecting pin, while moving along with the connecting pin. In this case, a lower portion of the cam bore is defined as the first bore portion extending in parallel to the axis of the head pipe, and hence, when the roller is rolled within the first bore portion, the arm and thus the pushing member are also moved in parallel to the axis of the head pipe. Therefore, when the upper end of the head pipe is pushed by the pushing member, the movement of the pushing member can be in a direction along the axis of the head pipe and thus, the head pipe can be clamped stably and reliably between the supporting pin and the pushing member in spite of the change in length of the head pipe.
According to a fifth aspect and feature of the present invention, in addition to the third or fourth feature, the pin-supporting plate is disposed at a location below the head pipe for turning movement about the axis parallel to the axis of the head pipe; the supporting pins individually corresponding to the plurality of types of head pipes are fixed to the pin-supporting plate, so that the supporting pins are disposed at a plurality of locations equally spaced apart from one another in a circumferential direction of the pin-supporting plate; and the apparatus further includes an index mechanism connected to the pin-supporting plate to alternatively bring one of the plurality of supporting pins to a position below the head pipe. With such arrangement, in accordance with the change in type of the vehicle body frame for the motorcycle, which is to be assembled, the supporting pin corresponding to the head pipe can be selected automatically and brought to the position below the head pipe, leading to an enhanced assembling efficiency.
According to a sixth aspect and feature of the present invention, in addition to the second feature, each of the front positioning means and the rear positioning means includes a guide wall which has a guide bore corresponding to a positioning bore provided in a positioned member forming a portion of the front frame subassembly or the rear frame subassembly to extend in a widthwise direction of the vehicle body frame, the guide wall being opposed to an outer side surface of the positioned member in a position where the guide bore corresponds to the positioning bore, a cylinder disposed coaxially with an axis of the guide bore on a side of the guide wall opposite from the positioned member, a plurality of movable rods which are capable of being fitted into the guide bore for selective interposition as well as removable insertion between the cylinder and the guide wall, each of the movable rods being releasably connected at one end thereof to the cylinder, and a plurality of types of positioning pins, each of which is formed into such a shape as to be capable of fitting into the positioning bore in any of a plurality of types of the positioned members, the positioning pins being individually fixed to the other ends of the movable rods.
With the arrangement of such sixth feature, one of the plurality of movable rods, which has the positioning pin corresponding to the type of the positioned member, is selected and brought to between the cylinder and the guide wall and removably fitted into the guide bore by connection with the cylinder. Thus, the positioning pin corresponding to the positioning bore in the positioned member can be fitted properly into the guide bore to position a frame member, thereby providing general-purpose properties to accommodate the assembling of any of the plurality of types of vehicle body frames for motorcycles, leading to a reduction in equipment cost.
According to a seventh aspect and feature of the present invention, in addition to the sixth feature, the apparatus further includes a rod-supporting plate disposed between the guide wall and the cylinder for turning movement about an axis parallel to the axis of the guide bore, the movable rods being disposed at the locations equally spaced apart from one another in the circumferential direction of the rod-supporting plate and retained on the rod-supporting plate for sliding movement in a direction parallel to the axis of the guide bore, and an index motor connected to the rod-supporting plate for driving the rod-supporting plate in turning movement, so that one of the movable rods can be alternatively brought to a position between the cylinder and the guide bore. With such arrangement, it is possible to provide, in a simple structure, an arrangement designed so that one of the plurality of types of positioning pins is selected in correspondence to a frame member to be positioned, and is brought to a position where it corresponds to the guide bore with a good accuracy.
According to an eighth aspect and feature of the present invention, in addition to the second feature, the rear clamp means formed to clamp and retain a pipe-shaped frame member forming a portion of the vehicle body frame and extending in the substantially longitudinal direction of the vehicle body frame includes a movable support which is capable of being moved in the longitudinal, widthwise and vertical directions of the vehicle body frame and is capable of being stopped at any position, a receiving member which is formed into a substantially V-shape to open upwards in a plane intersecting a lengthwise direction of the frame member, and is fixed to the movable support so as to be disposed below the frame member, a pushing member supported on the movable support for swinging movement in such plane to sandwich the frame member between the pushing member and the receiving member, and a drive mechanism provided between the movable support and the pushing member to drive the pushing member in swinging movement, each of surfaces of the receiving member and the pushing member opposed to the frame member being formed into such a shape as to be brought into spherical contact with the frame member.
With the arrangement of such eighth feature, the movable support is capable of being moved in the three-dimensional directions and stopped at any position. Therefore, the frame member can be clamped in spite of the change in outside diameter thereof by fixedly disposing the substantially V-shaped receiving member below the frame member at a location corresponding to the type of the frame member to be clamped, and by swinging the pushing member to sandwich the frame member between the pushing member and the receiving member. Moreover, the receiving member and the pushing member are brought into a spherical contact with the frame member and hence, even if the angle formed by the lengthwise direction of the frame member and a plane in which the receiving member and the pushing member are disposed is varied to some extent, the frame member can be reliably clamped between the receiving member and the pushing member. Therefore, it is possible to provide general-purpose properties to accommodate the assembling of any of a plurality of types of vehicle body frames for motorcycles, leading to a reduction in equipment cost.
The above and other objects, features and advantages of the invention will become apparent from the following description of the preferred embodiment taken in conjunction with the accompanying drawings.